Bearing assembly for wheelchair structures

ABSTRACT

A wheel hub and bearing assembly for an invalid supporting wheelchair, wherein the bearing structure includes a pair of axially aligned bearings arranged in side-by-side relationship with a common journal shaft extending therethrough, and with a common outer race being provided for the bearing structure. The elongated journal shaft is received within a sleeve mounted upon the frame means of the wheelchair, and the individual bearing races are disposed in spaced-apart relationship to accommodate shock-loading of the chair structure. For ease of removal of the wheels, the sleeve which receives the journal shaft as well as the journal shaft per se is provided with a generally radially extending pin receiving bore, and a locking bolt or pin is normally received therewithin.

1451 July 8, 1975 Moroney [54] BEARING ASSEMBLY FOR WHEELCHAIR 3,446,536 5/1969 Sutowski 308/ I91 X STRUCTURES 3,446,537 5/l969 SLltOWSki 308/19! X [75] Inventor: rR/lichard D. Moroney, Bloomington, Primary Examiner Leo priagna Assistant Examiner-Terrance L. Siemens [73] Assignee: Theradyne Corporation, Jordan, Attorney, Agent, or Firm-Orrin M. Haugen, Esq.

Minn.

22 Filed: Feb. 6, 1974 [57] ABSTRACT A wheel hub and bearing assembly for an invalid sup- [211 Appl' 439873 porting wheelchair, wherein the bearing structure includes a pair of axially aligned bearings arranged in [52] US. Cl. 280/242 WC; 297/DIG. 4 side-by-side relationship with a common journal shaft [51] Int. Cl B62m 1/14 extending therethrough, and with a common outer [58] Field of Search..... 280/242 WC; 308/290, 291-, race being provided for the bearing structure. The 297/DIG. 4 eiongated journal shaft is received within a sleeve mounted upon the frame means of the wheelchair, and [56] References Cited the individual bearing races are disposed in spaced- UNITED STATES PATENTS apart relationship to accommodate shock-loading of 1 136 200 4/1915 Adam 308,190 the chair structure. For ease of removal of the wheels, 2 427 430 9/1947 waded 2 13:11:31: 308/191 the sleeve which receives the Jhuma' shah as as 2:56|:6|6 7/195] Everest I 230/242 WC x the journal shaft per se is provided with a generally ra- 2,782,835 2/1957 Liebich...... 297/DIG. 4 dially extending P receiving bore, and a locking bolt 2,955,884 10/!960 Marshall.... 308/190 0r pin is normally received therewithin. 3,400,990 9/l968 Sato l 308/19l 3,428,376 2/1969 Zeller 308/190 5 Clam, 3 Drawmg Figures IIIIIIIIIIIIIIIIIIII f40 5o I 42 1 j l L 64 q I LIIlI/j/I/l/ll BEARING ASSEMBLY FOR WHEELCHAIR STRUCTURES BACKGROUND OF THE INVENTION The present invention relates generally to an improved invalid supporting wheelchair assembly, and more specifically to an improved wheel hub and bean ing assembly for such a chair. Essentially, the bearing assembly includes a pair of axially spaced-apart bearing races which are received within a single outer race, with the outer race being normally retained within a central sleeve of a wheel hub assembly. The axial disposition of the bearings, along with the journal shaft provides for stable and durable mounting of the wheels upon the wheelchair structure.

The bearing structures for wheelchairs are frequently subjected to shock-loading, particularly upon the positioning of an invalid within the chair. While the wheelchair is normally not subjected to shock-loading during periods of normal patient support, the shock-loading which occurs when the patient enters the chair is frequently high and unless the bearing assembly is properly designed, damage to the assembly can occur. Obviously, invalids supported in wheelchairs require smooth running of the bearing assemblies in order to avoid problems due to generation of decubitius ulcers along the patients body and the like. It has been found that durable and smooth-running bearing assemblies render the chairs more comfortable during use for the patients confined to these chairs.

In the past, wheelchair hub and bearing assemblies have normally been provided with either a single roller or needle bearing assembly, or a pair of roller bearing assemblies have been provided at opposed ends of the wheel hubs. While these assemblies have performed reasonably well under normal operating conditions, it has been found that neither has been totally satisfactory from the standpoint of withstanding shock-loading during patient entry into the chair. The wheel hub and bearing assembly of the present invention provides a means whereby shock-loading may be withstood without risking damage to the bearing assembly, and furthermore, the wheel assemblies per se may be detachably secured or coupled to the frame structure of the wheelchair.

SUMMARY OF THE INVENTION Briefly, in accordance with the present invention, an improved invalid supporting wheelchair is provided having frame means, seat means supported upon the frame means, and wheels mounted for rotation upon the frame means. The wheels include a central hub which is supported upon ajournal and bearing arrangement which includes an elongated journal shaft having the inner end thereof received within a wheel mounting sleeve, and with the outer end thereof having a pair of axially spaced bearing devices mounted thereon. A single outer race is provided radially outwardly of the bearing, with the outer race being rigidly secured within the confines of the wheel hub sleeve. The axial spacing of the bearing races, together with the elongated journal shaft provides a durable wheel hub and bearing assembly which is capable of enduring and withstanding severe shock-loading which occurs when patients are being placed into the chair.

Therefore, it is a primary object of the present invention to provide an improved invalid supporting wheelchair having a durable wheel hub and bearing assembly which includes an elongated journal means having axially spaced bearing means arranged thereon for receipt within the confines of a wheel hub sleeve.

It is a further object of the present invention to provide an improved invalid supporting wheelchair having durable wheel hub and bearing assemblies which are susceptible for use under shock-loading conditions.

Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a wheelchair structure having the improved wheel hub and bearing assembly of the present invention coupled thereto;

FIG. 2 is a vertical sectional view taken generally through the diameter of the journal shaft and bearing assembly supporting the wheels of the chair; and

FIG. 3 is a vertical sectional view taken along the line and in the direction of the arrows 33 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the preferred embodiment of the present invention, and as illustrated in FIGS. 1-3 of the drawing, the invalid supporting wheelchair generally designated 10 includes frame means generally designated I] which receive and retain patient supporting seat means 12 and backrest panel member 13 therewithin. The frame means includes a pair of generally forwardly disposed support posts I515, along with rearwardly disposed support posts as at l6l6. As is indicated, the frame assembly includes right and left supporting assemblies, with these assemblies being, of course, similar, one to another. Accordingly, the panels include a lower rail element 17, an intermediate rail 18, and an upper rail 19. Arm rest pads are arranged along the upper surface of the upper rail, such as at 20 and 21. The frame means is preferably collapsible, such as is illustrated in U.S. Pat. No. 2,635,703 and No. 2,824,597. Such collapsible or foldable wheelchair frames are, of course, in wide commercial use at the present time, and accordingly are readily commercially available.

For added stability in the side frames, metal panels are arranged along each side thereof, such as is illustrated at 21A and 218, these metal panels being provided for the purposes of enhancing the rigidity of the structure during normal operational use.

As is further conventional in wheelchair structures, a pair of leg rests are provided such as at 22 and 23, with these rests terminating in foot support pads 24 and 25. At the upper end of the frame means, such as at the upper end of rear post 16-46, a pair of handle grips are provided such as at 26 and 27 for assisting individuals in moving patients confined to the chair.

Also, as is conventional, a pair of main support wheels are provided such as is illustrated at 30 and 31, along with forwardly disposed castor wheels 32 and 33. The main wheels 30 and 31 are mounted within wheel hub and bearing assemblies generally designated 34, to be described more fully hereinafter, while the forwardly disposed castor wheels are journaled within the confines of castor support journals 35-35. As has been indicated, these assemblies are more fully dis- 3 closed in US. Pat. Nos. 2,635,703 and 2,824,597 referred to hereinabove.

Attention is now directed to FIGS. 2 and 3 of the drawings wherein the details of the wheel hub and bearing assemblies are illustrated. in this connection, the wheel hub and bearing assemblies generally designated 34 which, for purposes of clarity, may be described as wheel receiving spindle means, are mounted upon the frame means and operatively secured thereto. in this connection, a wheel mounting sleeve means 40 is provided, with this sleeve means being secured to post 16 by means of a suitable weld or the like, the fillets of which are illustrated at 4l4l. The inner end of sleeve 40 is provided with a dust sealing cap or the like as at 42, while the outer axial end of sleeve 40 receives a bearing assembly, generally designated 44, with a journal shaft 45 being axially received within the confines of sleeve 40. Journal shaft 45 is fabricated from a durable hardened steel, and has its inner end portion, as at 46, received within sleeve 40, with the outer end portion 47 receiving a pair of bearing means therealong. In this connection. a pair of circumferential grooves are provided as at and 51, these circumferential grooves forming the inner race of a bearing assembly. Bearing means in the form of balls 5252 are provided, with these balls running within the grooves 50 and 51, in a conventional fashion. An outer race in the form of sleeve 54 is provided over the bearings 5252, with outer race 54 being provided with end seals as at 55 and 56 to assist in the exclusion of dust and debris from the confines of the bearings.

Wheel hub means are provided, with the wheel hub means including a central sleeve 58 having hub flanges 59 and 60 secured to opposed ends thereof. Flange 60 includes a radially inwardly projecting portion 61, along with a radially outwardly projecting portion 62. An outer sleeve element 63 is provided to enhance the aesthetics of the assembly. Dust cap 64 is provided which, in combination with flange 61, further protects the environment from ingress of dust, dirt, and other debris.

As is apparent in the assembly, sleeve 58 is rigidly se cured to the outer surface of race 54, with conventional securing techniques being employed, such as, for example, securing techniques employing curable adhesives, welding, brazing, or the like. Thus, sleeve 58 is fast upon outer race 54, and will not move relative thereto.

As is apparent in the drawings, the outer bearing means defined by inner race 50 is disposed outwardly of the axial center of wheel hub assembly 34. Thus, the load is distributed along the length of the journal shaft, thus enabling the system to withstand shockloading such as is frequently encountered with devices of this type. Also, it will be observed that a substantial portion, approximately one-half, of the axial length of journal shaft 45 is received within the confines of wheel mounting sleeve 40. This also enhances the durability of the structure.

In order to releasably retain the individual wheel assemblies within the confines of wheel mounting sleeve 40, a through-bore is formed generally radially within sleeve 40, such as illustrated at 66, for receiving locking pin 67 therewithin. Locking pin 67 is preferably prepared from ordinary spring-steel, and when locked in place, will provide for releasable retention of the wheels within the confines of the chair assembly. A mating bore is formed within or along journal shaft 45, thus making it possible for pin 67 to extend generally radially therethrough. in lieu of a through-bore being formed in journal shaft 45, a circumferential groove may be provided which will permit pin 67 to be utilized without regard to orientation of the individual bores.

For added purposes of durability, a bearing assembly similar to that illustrated in FIGS. 2 and 3 may be rovided in the castor assemblies, such as within the castor sleeve portion 35. This bearing assembly will be equally durable in such an application.

I claim:

1. in an invalid supporting wheelchair having frame means, seat means supported upon said frame means, and wheel receiving spindle means mounted upon said frame means, said wheel receiving spindle means comprising:

a. wheel supporting spindle receiving sleeve means rigidly mounted upon said frame means, a bearing assembly having a journal shaft spindle extending laterally therefrom and having the inner end thereof received within said sleeve means;

b. means arranged along said journal shaft spindle and adjacent the outer end thereof defining a pair of axially spaced inner bearing races;

c. bearing means disposed along said inner races and outer race means disposed radially outwardly of said bearing means and retaining said bearing means radially therewithin, said outer race means comprising a bearing means retaining sleeve with axially spaced outer bearing races;

(1. wheel hub means comprising a central spindle receiving sleeve with hub flanges disposed at either end thereof and mounted radially outwardly of said bearing means and receiving said outer race means rigidly therewithin, and arranged to turn with said outer race means;

e. a generally radially extending bore formed within said wheel supporting spindle receiving sleeve means and having releasable locking pin means extending therethrough, and recess means formed along said journal means for receiving said releasable locking pin means therewithin.

2. The invalid supporting wheelchair as defined in claim 1 being particularly characterized in that said bearing means are spaced apart and disposed adjacent opposed axial ends of the central sleeve portion of said wheel hub means.

3. The invalid supporting wheelchair as defined in claim 1 being particularly characterized in that said bearing means are balls.

4. The invalid supporting wheelchair as defined in claim 2 being particularly characterized in that approximately one-half of the axial length of said journal shaft spindle is received within said central sleeve, with the other half being received within said wheel mounting sleeve means.

5. The invalid supporting wheelchair as defined in claim 1 being particularly characterized in that said bearing means are provided with radially extending seal elements adjacent the opposed ends of said outer race means. 

1. In an invalid supporting wheelchair having frame means, seat means supported upon said frame means, and wheel receiving spindle means mounted upon said frame means, said wheel receiving spindle means comprising: a. wheel supporting spindle receiving sleeve means rigidly mounted upon said frame means, a bearing assembly having a journal shaft spindle extending laterally therefrom and having the inner end thereof received within said sleeve means; b. means arranged along said journal shaft spindle and adjacent the outer end thereof defining a pair of axially spaced inner bearing races; c. bearing means disposed along said inner races and outer race means disposed radially outwardly of said bearing means and retaining said bearing means radially therewithin, said outer race means comprising a bearing means retaining sleeve with axially spaced outer bearing races; d. wheel hub means comprising a central spindle receiving sleeve with hub flanges disposed at either end thereof and mounted radially outwardly of said bearing means and receiving said outer race means rigidly therewithin, and arranged to turn with said outer race means; e. a generally radially extending bore formed within said wheel supporting spindle receiving sleeve means and having releasable locking pin means extending therethrough, and recess means formed along said journal means for receiving said releasable locking pin means therewithin.
 2. The invalid supporting wheelchair as defined in claim 1 being particularly characterized in that said bearing means are spaced apart and disposed adjacent opposed axial ends of the central sleeve portion of said wheel hub means.
 3. The invalid supporting wheelchair as defined in claim 1 being particularly characterized in that said bearing means are balls.
 4. The invalid supporting wheelchair as defined in claim 2 being particularly characterized in that approximately one-half of the axial length of said journal shaft spindle is received within said central sleeve, with the other half being received within said wheel mounting sleeve means.
 5. The invalid supporting wheelchair as defined in claim 1 being particularly characterized in that said bearing means are provided with radially extending seal elements adjacent the opposed ends of said outer race means. 